826
32072H–AVR32–10/2012
AT32UC3A3
Figure 31-8. Mixing MultiMedia and SD Memory Cards with Two Slots
When the MCI is configured to operate with SD memory cards, the width of the data bus can be
selected in the SDCard /SDIO Bus Width field in the SDCR register (SDCR.SDCBUS).
for details.
In the case of multimedia cards, only the data line 0 is used. The other data lines can be used as
independent GPIOs.
When more than one card (MMC or SD) is plugged to the device, it is strongly recommended to
connect each card’s clock to a dedicate MCI CLK pin of the device. Otherwise, Compliance to
specifications is not guaranteed.
31.6.2
MultiMedia Card Operations
After a power-on reset, the cards are initialized by a special message-based MultiMedia Card
bus protocol. Each message is represented by one of the following tokens:
• Command: a command is a token that starts an operation. A command is sent from the host
either to a single card (addressed command) or to all connected cards (broadcast
command). a command is transferred serially on the CMD line.
• Response: a response is a token which is sent from an addressed card or (synchronously)
from all connected cards to the host as an answer to a previously received command. A
response is transferred serially on the CMD line.
• Data: data can be transferred from the card to the host or vice versa. Data is transferred via
the data line.
Card addressing is implemented using a session address assigned during the initialization
phase by the bus controller to all currently connected cards. Their unique CID number identifies
individual cards.
4
9
23
15
6
7
8
SDCARD
DATA[7:0]
CMD[0]
CLK
DATA[11:8]
CMD[1]
1 2 3 4 5 6
MMC1
7
910
1213 8
11
1 2 3 4 5 6
MMC2
7
910
1213 8
11
1 2 3 4 5 6
MMC3
7
910
1213 8
11
CLK
Summary of Contents for AT32UC3A3128
Page 61: ...61 32072H AVR32 10 2012 AT32UC3A3 PLLEN PLL Enable 0 PLL is disabled 1 PLL is enabled...
Page 592: ...592 32072H AVR32 10 2012 AT32UC3A3 Manchester Configuration Register on page 614...
Page 989: ...989 32072H AVR32 10 2012 AT32UC3A3 37 2 Package Drawings Figure 37 1 TFBGA 144 package drawing...
Page 991: ...991 32072H AVR32 10 2012 AT32UC3A3 Figure 37 3 VFBGA 100 package drawing...
